AKSU ÇAYI ÜST HAVZASI’NDA (ANTALYA, TÜRKİYE) YÜZEY SUYU KALİTESİNİN ÖTROFİKASYON VE HİDROJEOKİMYASAL ÖZELLİKLER AÇISINDAN DEĞERLENDİRİLMESİ

Öz

Bu çalışmada, Aksu Çayı Üst Havzası’ndaki yüzey sularının kalite özellikleri hidrojeokimyasal süreçler ve trofik durum göstergeleri birlikte değerlendirilmiştir. Bu kapsamda fiziksel parametreler, majör iyon bileşimi, besin tuzları ve klorofil-a konsantrasyonları analiz edilmiş; su kalitesi Yerüstü Su Kalitesi Yönetmeliği (YSKY) ve Carlson Trofik Durum İndeksi (TSI) çerçevesinde yorumlanmıştır. Elde edilen bulgular, yüzey sularının baskın olarak Ca–Mg–HCO₃ tipinde olduğunu ve su kimyasının büyük ölçüde karbonat çözünmesine bağlı doğal hidrojeokimyasal süreçler tarafından kontrol edildiğini göstermektedir. Bununla birlikte, bazı istasyonlarda Na⁺ ve Cl⁻ konsantrasyonlarında gözlenen artışlar, evapokonsantrasyon ve antropojenik etkilerle ilişkili olabileceğine işaret etmektedir. Besin tuzu konsantrasyonlarının bazı noktalarda yüksek değerlere ulaşmasına karşın klorofil-a seviyelerinin görece düşük kalması, biyolojik üretimin yalnızca besin tuzu varlığı ile değil, hidrodinamik ve fiziksel sınırlayıcı faktörler tarafından da kontrol edildiğini düşündürmektedir. Carlson TSI sonuçları, toplam fosfora dayalı olarak bazı istasyonlarda yüksek trofik seviyelere işaret ederken, klorofil-a temelli değerlendirmeler daha düşük trofik düzeyler ortaya koymuştur. Bu durum, havzada henüz belirgin bir ötrofikasyon gelişmemiş olmakla birlikte potansiyel bir risk bulunduğunu göstermektedir. İstatistiksel analizler, su kalitesinin karbonat çözünmesi, evapokonsantrasyon ve antropojenik girdiler olmak üzere üç temel süreç tarafından kontrol edildiğini ortaya koymaktadır. Bu çalışma, hidrojeokimyasal süreçler ile trofik durum göstergelerinin birlikte değerlendirilmesinin, yüzey suyu kalitesinin bütüncül olarak yorumlanmasında etkili bir yaklaşım sunduğunu ortaya koymaktadır.

Anahtar Kelimeler

• Aksu Çayı Üst Havzası
• Su Kalitesi
• Hidrojeokimya
• Trofik Durum İndeksi
• Evapokonsantrasyon

Destekleyen Kurum

Süleyman Demirel Üniversitesi Bilimsel Araştırma Projeleri Koordinasyon Birimi

Proje Numarası

FDK-2022-8702

Etik Beyan

Yazarlar tarafından herhangi bir çıkar çatışması beyan edilmemiştir.

Teşekkür

Bu çalışma Süleyman Demirel Üniversitesi Bilimsel Araştırma Projeleri Koordinasyon Birimi tarafından FDK-2022-8702 nolu proje kapsamında desteklenmiştir.

ASSESSMENT OF SURFACE WATER QUALITY IN THE UPPER AKSU RIVER BASIN (ANTALYA, TÜRKİYE) IN TERMS OF EUTROPHICATION AND HYDROGEOCHEMICAL CHARACTERISTICS

Öz

This study evaluates the water quality characteristics of surface waters in the Upper Aksu River Basin by jointly assessing hydrogeochemical processes and trophic status indicators. In this context, physical parameters, major ion composition, nutrients, and chlorophyll-a concentrations were analyzed, and water quality was interpreted within the framework of the Surface Water Quality Regulation (SWQR) and the Carlson Trophic State Index (TSI). The results indicate that surface waters are predominantly of the Ca–Mg–HCO₃ type and that water chemistry is largely controlled by natural hydrogeochemical processes associated with carbonate dissolution. However, increases in Na⁺ and Cl⁻ concentrations observed at certain stations suggest that evapoconcentration and anthropogenic influences may also play a role. Despite elevated nutrient concentrations at some locations, relatively low chlorophyll-a levels indicate that biological productivity is not solely governed by nutrient availability but is also influenced by hydrodynamic and physical limiting factors. Carlson TSI results reveal high trophic levels based on total phosphorus at certain stations, whereas chlorophyll-a-based assessments indicate lower trophic conditions. This discrepancy suggests that, although a clear eutrophication process has not yet developed in the basin, there is a potential risk. Statistical analyses demonstrate that water quality is controlled by three main processes: carbonate dissolution, evapoconcentration, and anthropogenic inputs. The findings highlight that the integrated evaluation of hydrogeochemical processes and trophic indicators provides an effective approach for a comprehensive interpretation of surface water quality. Statistical analyses reveal that water quality is controlled by three main processes: carbonate dissolution, evapoconcentration, and anthropogenic inputs. These findings highlight the sensitivity of the basin and emphasize the importance of nutrient management and continuous monitoring for sustainable water resource management.

Anahtar Kelimeler

• Upper Aksu River Basin
• Water Quality
• Hydrogeochemistry
• Trophic State Index
• Evapoconcentration

Destekleyen Kurum

Suleyman Demirel University Scientific Research Projects Coordination Unit

Proje Numarası

FDK-2022-8702

Etik Beyan

No conflict of interest was declared by the authors

Teşekkür

This study was supported by the Scientific Research Projects Coordination Unit of Süleyman Demirel University under project number FDK-2022-8702.

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